Underwater lighting devices used in swimming pools for safety and convenience reasons must be so protected from contact with the water in the pool that the chances of an electrical short in the pool are minimized to the greatest extent possible. In connection with in-ground pools, electrical lighting devices are normally mounted in the walls of the pool and are sealed in the wall by elaborate and costly encasements (see U.S. Pat. Nos. 4,216,411; 5,607,224; 5,045,978; 5,051,875; and 4,574,337). Such electrical lighting devices are intended to be installed, maintained and serviced only by professional, qualified technicians. In regard to above-ground pools, these are much less expensive pools than in-ground pools and are often installed and maintained by the homeowner. Since the walls of an above-ground pool are made of thin flexible materials, e.g. plastics or light metal panels and the like, underwater electrical lighting devices cannot be easily mounted through the walls of the above-ground pool, as they are with in-ground pools (see U.S. Pat. No. 4,503,489) and should be mounted on pool wall structures, e.g. metal or plastic support ledges and the like. Since such underwater electrical lighting devices would, most often, be installed and maintained by the homeowner of the above-ground pool, such lighting devices must be easily installed (without any substantial chance of harmful error), easily maintained (again without any substantial chance of harmful error), and relatively inexpensive.
Heretofore, the lighting of above-ground swimming pools has been achieved, mainly, by lighting devices that mount, at least in part, above the surface of the water in the pool and are attached to some upper structure of the pool (see U.S. Pat. No. 4,053,758). This allows an inexpensive lighting device which can be easily maintained by the homeowner and is simple to install. However, such lighting devices mainly illuminate the surface of the pool, and much of the light is reflected from that surface as glare and does not enter into the depths of the water in the above-ground pool. As a result of the glare and lack of lighting of the depths, during the evening hours, it is difficult to see what objects may be in the above-ground pool. It is, of course, a safety concern if the above-ground pool lighting devices do not illuminate substantially all of the depths of the water in the pool, and one cannot accurately see if a child, for example, a pet or hazardous object may be in the depths of the pool.
Some attempts have been made to provide underwater lighting devices for above-ground pools, but these devices suffer from a number of disadvantages. Firstly, and mainly, they are simply waterproofed adaptations of lighting devices designed for use in environments other than under water. Some use self-contained batteries (see U.S. Pat. No. 4,394,716). Others use sealed beam lamps (see U.S. Pat. No. 5,089,945) or sealed lamps (see U.S. Pat. No. 4,947,304). The illumination, therefore, is spread over a large conical angle, symmetric to the reflector conjugate axis and much of that light travels to the surface of the pool water where it is reflected. The use of a reflector helps to direct light to the front. However, conventional reflector designs limit the light beam angle to well below 180.degree.. In addition, these adaptations require very special waterproofing and cannot be maintained by the usual homeowner. Indeed, many of these devices should not be installed by the average homeowner.
It would, therefore, be of a decided advantage to the art to provide an underwater safety lighting device for swimming pools, and especially above-ground swimming pools. It would be a further advantage to provide such a device which can be simply and easily installed by the homeowner, easily and safely maintained by the homeowner, and one which does not cause glare or transmit substantial light to the surface of the water where it is lost to the atmosphere but transmits most of the light into and to the depths of the pool, such that objects in the pool can be easily observed during the dark hours.